The effect of COVID-19 on placental functioning in South African pregnancies: investigation of kisspeptin expression and vascular and inflammatory alterations

The coronavirus disease 2019 (COVID-19) pandemic has passed; however, its long-term effects are yet to be determined. Pregnant women and their neonates faced a higher risk for complications during this pandemic as COVID-19 was reported to result in oxidative and inflammatory stress and the cytokine storm, which would impact pregnancy, namely the trophoblast invasion and placental development and functioning. Therefore, this study aims to determine the effect of COVID-19 on the placental functioning in South African pregnancies through the analysis of kisspeptin and placental morphology. Immunohistochemical analyses of placental samples were performed to detect the expression of kisspeptin. Histopathological analysis was conducted to identify vascular and inflammatory alterations. This study demonstrated that COVID-19 results in a significantly increased expression of placental kisspeptin in both the central (p = 0.001) and peripheral (p < 0.0001) regions as compared with the placentae from control pregnancies. Upon further analysis, the placentae from COVID-19 pregnancies also presented with severe inflammation and maternal and fetal vascular malperfusion compared with the control placentae. A significantly increased expression of placental kisspeptin was observed in COVID-19 positive pregnancies, implying impaired placental functioning. This was further supported by vascular and inflammatory alterations observed in COVID-19-positive placentae, which may suggest that trophoblast invasion was compromised. To date, there still exists small clusters of COVID-19 outbreaks, and our findings highlight the importance of the future surveillance of these mothers and neonates in COVID-19 pregnancies in South Africa, as neonates from other countries have presented with abnormalities.